本文实例讲述了silverlight实现图片局部放大效果的方法。分享给大家供大家参考，具体如下：
很多购物平台中(比如京东购物)，浏览产品详情时都有这种效果，前几天看到有朋友问SL能不能实现，当然可以
界面:
1.左侧小图片(用一个矩形Fill一张图片即可)
2.左侧半透明矩形
3.右侧大图片(用一个Canvas设置Clip裁剪可视区域作为蒙板，图片放置在Canvas中即可)
原理：
获取左侧半透明矩形的相对位置，然后动态调整右侧大图的Canvas.Left与Canvas.Top
需要知道以下技术点:
1.Clip的应用
2.如何拖动对象
3.拖动时的边界检测
4.动态调整对象的Canvas.Left与Canvas.Top属性
尺寸要点:
1.右侧大图可视区域与左侧半透明矩形的“长宽比例”应该相同
2.“图片原始尺寸长度比” 应该 “与左侧小图片长度比”相同
3.图片原始大小/左侧小图大小 = 右侧可视区域大小/半透明矩形大小
关键代码：
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
|
using System.Windows;using System.Windows.Controls;using System.Windows.Input;namespace PartMagnifier{ public partial class MainPage : UserControl { bool trackingMouseMove = false; Point mousePosition; public MainPage() { // 为初始化变量所必需 InitializeComponent(); } private void LayoutRoot_Loaded(object sender, System.Windows.RoutedEventArgs e) { Adjust(); } private void Rectangle_MouseLeftButtonDown(object sender, MouseButtonEventArgs e) { FrameworkElement element = sender as FrameworkElement; mousePosition = e.GetPosition(element); trackingMouseMove = true; if (null != element) { element.CaptureMouse(); element.Cursor = Cursors.Hand; } Adjust(); Debug(); sb.Begin();//标题动画，可去掉 } private void Rectangle_MouseMove(object sender, MouseEventArgs e) { FrameworkElement element = sender as FrameworkElement; if (trackingMouseMove) { double deltaV = e.GetPosition(element).Y - mousePosition.Y; double deltaH = e.GetPosition(element).X - mousePosition.X; double newTop = deltaV + (double)element.GetValue(Canvas.TopProperty); double newLeft = deltaH + (double)element.GetValue(Canvas.LeftProperty); if (newLeft <= 10) { newLeft = 10; } if (newLeft >= 130) { newLeft = 130; } if (newTop <= 10) { newTop = 10; } if (newTop >= 85) { newTop = 85; } element.SetValue(Canvas.TopProperty, newTop); element.SetValue(Canvas.LeftProperty, newLeft); mousePosition = e.GetPosition(element); Adjust(); if (mousePosition.X <= 0 || mousePosition.Y <= 0) { return; } Debug(); } } private void Rectangle_MouseLeftButtonUp(object sender, MouseButtonEventArgs e) { FrameworkElement element = sender as FrameworkElement; trackingMouseMove = false; element.ReleaseMouseCapture(); mousePosition.X = mousePosition.Y = 0; element.Cursor = null; } /// <summary> /// 调试信息 /// </summary> void Debug() { txtResult.Text = "鼠标相对坐标：" + mousePosition.ToString() + "\n小框left：" + rect.GetValue(Canvas.LeftProperty) + ",小框top：" + rect.GetValue(Canvas.TopProperty) + "\n大图left：" + ((double)img.GetValue(Canvas.LeftProperty)).ToString("F0") + ",大图right：" + ((double)img.GetValue(Canvas.TopProperty)).ToString("F0"); } /// <summary> /// 调整右侧大图的位置 /// </summary> void Adjust() { double n = cBig.Width / rect.Width; double left = (double)rect.GetValue(Canvas.LeftProperty) - 10; double top = (double)rect.GetValue(Canvas.TopProperty) - 10; double newLeft = -left * n; double newTop = -top * n; img.SetValue(Canvas.LeftProperty, newLeft); img.SetValue(Canvas.TopProperty, newTop); } }} |
希望本文所述对大家C#程序设计有所帮助。
